Artificial Chromosomes
A variety of artificial chromosomes for use in plants and animals, particularly higher plants and animals are available. In particular, U.S. Pat. Nos. 6,025,155 and 6,077,697 provide heterochromatic artificial chromosomes designated therein as satellite artificial chromosomes (SATACs) and now designated artificial chromosome expression systems (ACes). These chromosomes are prepared by introducing heterologous DNA into a selected plant or animal cell under conditions that result in integration into a region of the chromosome that leads to an amplification event resulting in production of a dicentric chromosome. Subsequent treatment and growth of cells with dicentric chromosomes, including further amplifications, ultimately results in the artificial chromosomes provided therein. In order to introduce a desired heterologous gene (or a plurality of heterologous genes) into the artificial chromosome, the process is repeated introducing the desired heterologous genes and nucleic acids in the initial targeting step. This process is time consuming and tedious. Hence, more tractable and efficient methods for introducing heterologous nucleic acid molecules into artificial chromosomes, particularly ACes, are needed.
Therefore, it is an object herein to provide engineered artificial chromosomes that permit tractable, efficient and rational engineering of artificial chromosomes.